Refrigerating apparatus



Jan. as, 1935. K 1,987,510

REFRIGERATING APPARATUS Original Filed March 31, 1928 2 Sheets-Sheet 1J. G. KING 1,987,510 REFRIGEHATING APPARATUS Original Filed March 31,1928 2 Sheets-Sheet 2 Patented Jan. 8, 1935 UNITED STATES PATENT OFFICEREFRIGERATING APPARATUS Jesse G. King, Dayton, Ohio, assignor toFrigidaire CorporatiomDayton, Ohio, a. corporation of Delaware 8 Claims.

This invention relates to refrigerating systems.

It is an object of the present invention to provide an improvedrefrigerating system, the operation of which can be adjusted by the userto produce any one of a plurality of temperatures within the evaporatorof the refrigerating system by the manipulation of an easily accessiblemanual means.

It is a further object of the present invention to provide an improvedrefrigerating system, the operation of which may be varied to produceany one of a plurality of temperatures by varying the adjustment of thecontrol device by the manipulation of an easily accessible manual meansforming a part of the control device to any one' of a plurality ofselected positions; the control device with the manipulating device inone of its selected positions being calculated to start the operation ofthe system at a temperature above 32 F. to thereby provide for cyclingdefrosting.

It is a still further object of this invention to provide arefrigerating system including a control mechanism which normallymaintains a predetermined mean temperature in the cooling unit and whichcan be rendered operative or inoperative to temporarily modify thetemperature of the cooling unit by the manipulation of an easilyaccessible manual device, the control also including provisions forautomatically returning the manipulating means to its original positionafter a predetermined modified temperaturecondition of the cooling unitor for permitting the continued operation of the refrigerating apparatusto produce the modified temperature condition of the cooling unit.

Referring to the drawings Fig. 1 shows a refrigerating circuit embodyingthe improved control device of the invention.

Fig. 2 is a side view partly in section of a control device for thesystem of Fig. 1 said device being provided with the improved modifyingmeans of the invention.

Fig.3 is an illustration of the modifying device.

Fig. 4 shows the'control device of the invention with the contacts aboutto open.

Fig. 5 illustrates the same in open position.

Fig. 6 is a curve illustrating normal operation of the refrigeratingcircuit.

Fig. 7 is a curve showing normaloperation with interposition of anabnormal cycle and subsequent return to normal.

Fig. 8 illustrates normal operation with abnormal operation continuedfor a desired length of time and a final return to normal.

A mechanical type of refrigerator is represented diagrammatically by therefrigerating circuit shown in Fig. 1. This circuit includes theevaporator 10 and its associated ducts 11, supplied with a suitablerefrigerant such as sulphur dioxide by means of a compressor 12 drivenby a motor 13. The refrigerant after being passed thru a condenser 14and collected in a receiver 15 is fed to the refrigerating element thrua pipe 16 and is withdrawn therefrom thru pipe 17 and returned to thecompressor.. A control mechanism, shown in the form of a switch isconnected into the suction side of the system as at 18 and is used toregulate the operation of the system. The control device is showndiagrammatically in Fig. 1 and comprises a flexible metal bellows 19connected by means of the pipe 23 to the pipe 17, as indicated at 18,and adapted by a lever system 20 to operate the switch 21 which controlsthe operation of the motor.

Referring in detail to the drawings, the control mechanism shown in Fig.2 and diagrammatically indicated in Fig. 1 comprises a pressure operateddevice such as a switch which is arranged to make and break the circuitof the electric motor driving the compressor. This switch includes apressure responsive means consisting of a hollow metallic bellows 19which is sealed at the top by a plate 22 and which is connected at thebottom by means of pipe 23 to the refrigerating system-circuit. 'Anoperating member or lever 24 pivoted at 25 is adapted to follow themovements of plate 22 since it is pivoted thereto as at 26. Theoperation of lever 24 causes the switch contacts 25' and 26 to bebrought in contact with each other or separated as shown in Figs. 4 and5, and this operation is accomplished through the intermediary ofconnection levers 26" and 27, which are pivoted to the lever 24 and tothe switch contact 25'.

The snap action of the lever 24 is produced by a cam system comprisingnose 28 and a hardened steel roller 29 which engages therewith. Thisstructure is described in the copending application of Otto M. Summers,Serial No. 123,420, filed July 19, 1926, now Patent 1,802,486 datedApril 28, 1931.

As the pressure builds up within the flexible metal bellows 19 thelatter expands and since the lever 24 is pivoted at 25 to a portion ofthe frame 30 of the control device it is evident that the bellows willraise the operating lever 24. The upward movement ofthe lever 24 is,however, resisted by a yieldable adjusting system comprising a coiledspring 31 operating against a plunger 32 a d pring 31 held by a suitablehousing 33,

embodiment 'of the present invention and co which latter provides ameans for adjusting the tension of the spring 31 and, consequently, theforce exerted against lever 24. A. suitable anvil 34 is provided for thecoaction of the plunger 32 against the lever 24. A spring 35 carried bya rod 36 attached to the lever beyond the point of its attachment to thebellows e. g., as at 37, is used for resisting the descent of the lever24 when the pressure in the bellows 19 decreases.

It is apparent that the upward and downward movements of the lever 24are effected with sudden snap actions due to the construction of cam 28and roller 29, and the arrangement of the pivots so that the switchcontacts 25', 26' are opened and closed suddenly thus preventing thedrawing of arcs at these points.

The spring 35 and the resilient adjusting system composed of spring 31and retaining cap 33 comprise the adjusting mechanism and are preferablyso adjusted as to produce what may be termed a normal predeterminedtemperature,

- that is, a temperature suitable for ordinary operation of therefrigerator.

The adjusting mechanism of the control device hereinbefore described maybe manipulated to vary the temperatures at which the switch will operateto start and stop the system. This manipulating means is not, however,easily accessible and in fact is designed primarily for the use of anexpert serviceman.

This temperature may be sufilcient to cool footstufls stored in thecrypts of the refrigerating element or in the compartment cooled therebyand may be sumcient to produce freezing if the food is exposed longenough to this temperature. However, if it should be decided to hastenthe freezing action it is apparent that the normal operation of thedevice must be modified in some manner so that the refrigerator istemporarily maintained at a lower temperature.

To provide for this modified operation of the refrigerating system, Ihave included in the adjusting mechanism of the controlling device abovedescribed, an additional means that may be moved by the operation of aneasily accessible manual means into the path of the lever 24 on itsdownward movement so that a lower temperature within the evaporator isrequired to move the switch to its position. It is apparent that byinterposing a resistance to its downward movement the operationof theswitch contacts will be resisted and that the system will continueoperating for a longer period of time thus prolonging the freezlngcycle. A suitable method of interposing such a resistance is illustratedilnsfhe ts in placing a resilient obstruction in the path of thedownward movement of the lever 24, so that its movement is retarded bythe tension of the spring interposed between the lever 24 and the frameof the apparatus.

The resilient blocking means used in the preferred embodiment of theinvention comprises a lever system including a member 38 pivoted to link39 which in turn is iournaled in the stirrup 40 carried by the frame 41of the control device. The link 42 serves to connect the member 38 witha rod 43 which slides vertically in a guide in the frame 41. A spring 44is disposed intermediate the link 39 and the member 38. There islikewise provided a guide rod 45 having adjusting nuts 48 and 51 foradjusting the tension of the spring 44 with respect to its effect uponlink 39 and member 38. It is, therefore, obvious that link 33 isresiliently pivoted on link 39 at the point 47. Member 38 is providedwith. a notch 48 which engages a pin 49 carried by the lever 24. It isapparent that this resilient blocking system may be pushed out of theway of the pin 49 so that the lever may move unhindered in an up anddown direction and that the notch 48 may be snapped in engagement withpin 49 so that upon its downward movement the lever 24 will drag member38 down with it against the pressure of spring44. This will impose ablock or drag upon the lever 24, the intensity of which may be regulatedby suitable tensioning of the spring 44.

The resilient blocking or modifying system just described is so arrangedthat normally it tends to lie out of the path of the descending pin 49but it is evident that the resilient modifying system may be snappedinto engagement with the pin. The result of this retardation of downwarddescent of the lever will be to cause a prolongation of the freezingcycle, in other words, a longerthan-normal operation of the compressor.Upon the ascent of the lever 24 the resilient system will fall out ofthe way and leave the control apparatus free to function normally.

If it is decided, however, to continue the modifying operation of thecontrol device the resilient system above mentioned is snapped intoplace and locked in place by turning the nut 50 to the extremity of theguide rod 43. The refrigerating system will then work continuously withmodified prolonged freezing cycle and thus produce amore rapid freezing.

The various positions of the modifying device are shown in the drawings.In Fig. 2, the control mechanism is shown arranged for operation asdetermined at the factory. In this case the resilient blocking ormodifying device is shown lying in its inoperative position, out-of theway of pin 49 carried by lever 24. In Fig. 4, the modifying device isshown snapped into place with the switch contacts 25' and 26' closed. Inthis position one prolonged cycle of operation or quickfreezing cyclewill be produced and after the modifying device falls out of the way ofthe pin 49 as shown in Fig. 5, which will occur when the lever 24ascends, the control device will return to its normal function. In Fig.3 the modifying device is shown locked in position for producing aplurality of freezing cycles. These freezing cycles will continue untilthe modifying device is released by. unscrewing the nut 50 and allowedto fall back out of the way of the lever 24 so as to permit the lever 24to operate on normal cycle operation.

The operation ofthe device may be explained graphically by the curveshown in Figs. 6 to 8 inclusive.

These graphs, in which the closely spaced lines represent vacuum ininches of mercury and the widely spaced lines pressure in pounds ,persquare inch, represent the conditions of temperature or pressureexisting in the refrigerating system as plotted against cycles or time.

Fig. 6 represents normal cyclic operation. Fig. '7 shows the compressoroperating phase of one cycle prolonged by the modifying means of theinvention. Fig. 8 illustrates the compressor operating phases asprolonged for a plurality of cycles by the modifying apparatus.

In these graphs the points A represent the pressures at which the switchcloses to start the apparatus, and B the points when the switch opens tostop the compressor. The points C rep- ,resent the pressure temperaturecondition existing in the apparatus at the instant the-switch opensafter the same is affected by the modifying device. The one quickfreezing cycle of Fig. 7 is produced by snapping the modifying deviceinto operative position. Upon the termination of the cycle the modifyingdevice falls out of the way and the control switch resumes its normalcyclic operation. If the modifying device is locked in operativeposition by turning the nut 50, a succession of quick-freezing cycleswill be produced as shown 'by Fig. 8. By unscrewing the nut 50 themodifying device returns to its normal inoperative position.

From the graphs it will be observed that the control is effected bychanging the lower temperature limits and leaving the upper temperaturelimits unchanged. In this manner defrosting will occur at every cycle.

By means of the arrangement shown a convenient means is provided-forproducing at will either a single quick freezingcycle or a plurality ofsuch cycles and for restoring the system automatically to normal cyclicfunctioning after the single quick-freezing cycle has terminated. Meansare also provided for manually restoring the system to normal cyclicoperation upon the termination of any desired number -of quickfreezingcycles.

By virtue of this invention, if desired, defrosting of the cooling unitcan be secured during each cycle. It is desirable in some instances thatthe cooling unit be free from frost. The control device in such a casecan be set so that the higher temperature limit is above the freezingpoint of water. In this manner, during each cycle of operation the frostwhich collects during the operation of the compressor is melted off. Bymeans of the arrangement of the invention quick freezing can be effectedwithout disturbing the upper temperature of the cooling unit since onlythe lower temperature range is affected. Thus, during quick freezingoperations the lower temperature limit being changed, a lower meantemperature is obtained in the cooling unit while the upper temperaturelimit is maintained the same.

While I have shown the adjusting mechanism in individual parts such asthe spring 35, the spring 31, and the resilient blocking means, itshould be understood that other forms of adjusting mechanism such as asingle spring having two separate manipulating means for varying theefiectiveness thereof may equally as well be used.

It should also be understood that the low pressure control 23 is ineffect a control responsive to the temperature of the evaporator sincethe pressure within the evaporator varies directly with the temperaturetherein.

This application is a division of my copending application Serial No.266,284 filed March 31, 1928.

I claim:

1. A refrigerating system comprising in combination an evaporator, aliquefying unit for withdrawing gaseous refrigerant from and returningliquid refrigerant to the evaporator, control means for cyclicallyoperating the unit by starting and stopping the operation of the unit atpredetermined high and low temperatures to produce a mean averagetemperature in the evaporator, means for modifying the control means toproduce cycles of operation of said unit to efiect diflerent meantemperatures, said modifying means including means for rendering "saidmodifying. means inoperative to effect said control means after a singlecycle of operation, and means for rendering said last named meansinoperative whereby said liquefying unit will cycle continuously underthe control of said modifying means to continuously produce saiddifferent mean temperatures in said evaporator.

2. A refrigerating system comprising in combination an evaporator, aliquefying unit for withdrawing gaseous refrigerant from and supplyingliquid refrigerant to the evaporator, control means for normallycyclically operating the liquefying unit by starting and stopping saidunit at predetermined high and low temperatures respectively to producea predetermined mean average temperature in the evaporator, means formodifying the control means to produce continuous cycling of the-.liquefying unit to obtain a different mean average temperature in theevaporator, said modifying means including means for obtaining a singlecycle of operation of said liquefying unit to obtain said different meantemperatures and for returning said unit to its normal cyclicaloperation and manual means for controlling said modifying means.

3. A refrigerating system comprising in combination an evaporator, aliquefying unit for withdrawing gaseous refrigerant from and supplyingliquid refrigerant to the evaporator, control means for normallycyclically operating the liquefying unit by starting and stopping saidunit at predetermined high and low temperatures respectively to producea predetermined mean average temperature in the evaporator, i

means for modifying the control means to produce continuous cycling ofthe liquefying unit to obtain a lower mean average temperature in theevaporator, said modifying means including means for obtaining a singlecycle of operation of said liquefying unit to obtain said lower meanaverage temperature and for returning said unit to its normal cyclicaloperation, and manual means for controlling said modifying means.

4. A refrigerating system comprising in combination an evaporator, aliquefying unit for withdrawing gaseous refrigerant from and returningliquid refrigerant to the evaporator, control means for cyclicallyoperating the unit by starting and stopping the operation of theliquefying unit at predetermined high and low temperatures to produce amean average temperature in the evaporator, means for modifying thecontrol means to produce cycles of operation of said unit to effect alower mean temperature, said -modifying means including means forrendering tion of said unit by starting and stopping said unit atpredetermined high and low temperatures respectively, means formanipulating said adjusting mechanism, an additional means formanipulating said adjusting mechanism to adjust said control mechanismto each of a plu .rality of selected positions for effecting continuousintermittent operation of said unit between different predeterminedtemperatures, said control mechanism in one of said selected positionsbeing operative to start said unit when the temperature of theevaporator is above 32 F. while producing a mean average temperaturebelow 32 F., said last named, manipulating means comprising readilyaccessible manual means.

6. A refrigerating system comprising in combination an evaporator, aliquefying unit for supplying liquid refrigerant to and for withdrawinggaseous refrigerant from said evaporator, a control mechanism providedwith adjusting mechanism for effecting anintermittent operation of saidunit by starting and stopping said unit at predetermined high and lowtemperatures respectively, means for manipulating said adjustingmechanism, an additional means for manipulating said adjusting mechanismto adjust said control mechanism to any one of a plurality of selectedpositions for effecting continuous intermittent operation of said unitbetween difierent predetermined temperatures, said control mechanism inat least one of said selected positions being operative to start saidunit at a frost melting temperature while producing a mean averagetemperature suflicient to refrigerate food stuffs, said additionalmanipulating means comprising readily accessible manual means.

7. A refrigerating system comprising in combination an evaporator, apumping unit for removing vaporous refrigerant from said evaporator, acontrol mechanism provided with adjusting mechanism for effecting anintermittent operation of said pumping unit by starting and stoppingsaid pumping unit at predetermined high and low temperaturesrespectively, means for manipulating said adjusting mechanism, anadditional means for manipulating said adjusting mechanism to adjustsaid control mechanism to any one of a plurality of selected positionsfor eflecting a continuous intermittent operation of said unit betweendifferent predetermined temperatures, said control mechanism in one ofsaid selected positions being operative to start said pumping unit at afrost melting temperature while producing a mean average temperaturesumcient to refrigerate food stuffs, said additional manipulating meanscomprising readily accessible manual means for manipulating saidadjusting mechanism to and from the plurality of selected positions andmeans for limiting the' movement of said manual'means to prevent themovement of said adjusting mechanism to a position above or below thehighest and lowest selected position respectively. v 8. A refrigeratingsystem comprising in combination an evaporator, a liquefying unit forsupplying liquid refrigerant to and for withdrawing gaseous refrigerantfrom the evaporator, a control mechanism including a bellows responsiveto the temperature of the evaporator, said control mechanism beingprovided with adjusting mechanism for effecting an intermittentoperation of said unit by starting and stopping said unit atpredetermined high and low temperature limits respectively, means formanipulating said adjusting mechanism and additional means formanipulating said adjusting mechanism and selectively movable between aplurality of positions for adjusting said control mechanism within alimited range whereby to effect continuous intermittent operation ofsaid unit by starting and stopping said unit at different predeterminedtemperatures, said control mechanism with the second named manipulatingmeans in one cf said positions being operative to start said unit whenthe temperature of the evaporator is above 32 and to stop said unit whenthe temperature of the evaporator is below 32, said last namedmanipulating means comprising readily accessible manual means.

JESSE G. KING.

